Unable to erase authorization on Adobe Digital Editions on MacBook Air

I want to borrow e-copies of library books on Libby.  I have done this in the past with Overdrive.  I have an old Adobe account which uses my old defunct/inactive email address as the password.  It won't communicate any more with my library card which now uses my current email address.  So I want to erase it's authorization on Adobe Digital Editions  and authorize my new Adobe account which uses my current active email address.  However, when I try to do this I get the message:  "Unable to erase authorization.  Please try after some time."   I have been trying unsuccessfully for a week and have spent many hours with on-line chat support and a live agent - who directed me to this forum.   I have tried changing the email address on the old account to my new email but it is not accepted as it is already being used in  my new account.  I have tried changing passwords.  I have tried to access my Adobe Digital Editions account through an incognito window.   I have tried unsuccessfully to delete the new account hoping I could change the email on the old account to my current one.   I hope some one can help.